We appear to have a difference in terminology here. What is your definition of a "crescent wrench"?
Where I grew up a Crescent wrench was the most well known brand name for an adjustable wrench as shown here:
Specific sized wrenches, even if made by Crescent were "open end" or "box" wrenches.
If someone said "Hand me the Crescent wrench", you knew they meant the adjustable wrench.
If you do a Google search on Crescent wrench, the overwhelming majority (almost 100%) of the images are of adjustable wrenches, even if not made by Crescent.
I guess that's why I find the term "metric Crescent wrench" a little strange. My brain says "An adjustable wrench is neither metric nor imperial."